<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    #myChecbox:checked + p {
      background: red;
    }
  </style>
</head>
<body>
<label for="myChecbox">Click me!</label>
<input id="myChecbox" type="checkbox"/>
<p>This is a paragraph</p>
</body>
</html>
